A lot of people will tell you that there is no ego in ju jitsu. I can understand that it is humbling to be a 200 lb man getting choked and controlled by a smaller guy that is weaker than you. I understand that point of view. I understand that constantly being beaten up every day can be humbling. I understand that ju jotsu teaches you to be respectful and not underestimate a smaller guy, but ego is huge in ju jitsu and my explanation will be very quick.
The UFC. 20 years ago UFC 1 was basically the Gracie family wanting to prove that Brazilian Ju Jitsu was the best martial art in the world. It doesn't get any more egocentric than that. Think of it today the largest fighting platform in the world was started on the concept of a family in Brazil who wanted to prove they were the best. That to me is ego. Also remember when they used to go to dojos and challenge people to fights. Also any fighter during interviews they don't say things like I am ok I guess. They all say I am the best in the world no one can beat me.
The way I think ju jitsu does help with attitude is mostly in the dojo. You are more respectful of your partners and coaches after training. I also notice, I seem to treat people with more respect than I used to outside of the gym, that could just be from discipline. However I think ego is still and always will be in ju jitsu and martial arts. I think wanting to be the best and say your the best is what builds your desire to grow and try harder to get better. I think if you have an ego just control it and become the best you can be and still treat everyone with respect.